Fitk

Fixed

- Fixed parsing of `options` kwarg to `FisherBaseFigure`

Changed

- Replaced `**kwargs` of `fisher_matrix` method by `kwargs_signal` and `kwargs_covariance`
- Updated examples

Added

- Added `contour_levels_1d` and `contour_levels_2d` to `FisherFigure2D`

Added

- added `FisherBarFigure` class for bar-like plotting of constraints
- added `mark_fiducials` kwarg to `FisherFigure1D` and `FisherFigure2D`

Changed

- Renamed modules:
- `fisher_derivative` to `derivatives`
- `fisher_matrix` to `tensors`
- `fisher_plotter` to `graphics`
- `fisher_utils` to `utilities`
- `fisher_operations` to `operations`
- Updated docstrings